Combination engine-compressor



Sept. 28, 1965 'o. M. ULBING 3,208,439

COMBINATION ENGINE-COMPRESSOR Filed Feb. 14 1964 3 Sheets-Sheet 2 INVENTOR. 0mm M. UL Bl/VG F l 6 3 BY 9M WT ATTORNEY Sept. 28, 1965 o, M. ULBIN 3,208,439

COMBINATION ENGINE-COMPRESSOR Filed Feb. 14, 1964 5 Sheets-Sheet 5 a g INVENTOR.

5 20 OTMAI? M. ULBl/VG' 9M WTW ATTORNEY United States Patent Office Patent ed Sept. 28, 1965 3,208,439 COMBINATION ENGINE-COMPRESSQR Otmar M. Ulbing, Lisle, N.Y., assignor to Ingersoll-Rand Company, New York, N.Y., a corporation of New Jersey Filed Feb. 14, 1964, Ser. No. 344,845 6 Claims. (Cl. 123-46) This invention relates to the art of internal combustion engines and particularly to a combination internal combustion engine and gas compressor of the free-piston type.

The principal object of this invention is to provide an improved combination engine and compressor of simple construction which can be manufactured relatively inexpensively, is light in weight and of relatively small size and can be operated cheaply and easily by persons of little skill or knowledge in the technical arts.

Other important objects of this invention include the following: to provide a new type of fuel injection system for internal combustion engines; to provide a simple fuel injection system utilizing low pressures and relatively few elements; to provide an improved starting mechanism for free piston engines; to provide a free piston starting mechanism which can be safely used without danger of injury to the operator; and to provide a manual starting mechanism for a free piston engine which latches the piston in an expanded position until the mechanism is moved to a storage position.

The invention is described in connection with the following drawings wherein:

FIG. 1 is an axial section of a combination free piston engine and compressor embodying the concepts of this invention;

FIG. 2 is a section taken along line 2-2 of FIG. 1;

FIG. 3 is a section taken along line 33 of FIG. 1;

FIG. 4 is a fragmentary section of the combination engine and compressor showing the starting lever in its storage position;

FIG. 5 is a section similar to FIG. 4 showing the starting lever in a position forcing the engine piston to its extended position;

FIG. 6 is a section similar to FIGS. 4 and 5 showing the starting lever partially returned to its storage position; and

FIG. 7 is a section similar to FIG. 2 showing a modified embodiment.

The combination free piston engine and compressor 1, shown in FIG. 1, includes a finned internal combustion engine cylinder 2 and a finned compressor cylinder 3. The cylinders 2 and 3 are connected together in axial alignment with their open ends in engaged and opposed relationship. Each cylinder 2 and 3 carries an outwardly extending radial flange 4 at the periphery of its open end. The flanges 4 seat on each other and are locked together by an encircling channel ring 5. The interior of the channel ring 5 has inwardly diverging surfaces engaging outwardly converging surfaces on the flanges 4 which cooperate to wedge the flanges 4 together as the channel ring 5 is drawn together tightly on the flanges by conventional means (not shown).

The internal combustion engine cylinder 2 is closed at its outer end by an engine head 7 and contains a reciprocating piston 8. The piston 8 is fixed to an axially 5 extending piston rod 9 which projects inwardly from the piston 8 to the interior of the compressor cylinder 3. A partition 10 is located at the inner end of the engine cylinder 2 and is clamped in place between the cylinders 2 and 3. The interior of the compressor cylinder 3 is smaller in diameter than the interior of the engine cylinder 2 so that the end of the compressor cylinder 3 provides a shoulder 11 to engage and support the partition 10. The partition 10 is urged against the shoulder 11 by a spring 12 engaged between it and the engine piston The main purpose of the spring 12 is to bias the piston 8 toward the engine head 7.

The compressor cylinder 3 contains a reciprocating compressor piston 14. The piston 14 contains several inlet ports 15 closed by a spring-loaded disc valve 16 which opens during the suction stroke of the compressor piston 14- and closes during its compression stroke. The compressor cylinder 3 contains an outlet port 17 closed by a spring-loaded plunger valve 18. The valve 18 is loaded to remain closed until the pressure in the compressor cylinder reaches a predetermined value, say p.s.i.

Means is provided for withdrawing the engine piston 8 to its extended position wherein the spring 12 is compressed so that, when it is released, it will force the piston 8 toward the engine head 7 for starting the engine. This means includes a starting lever 20 pivoted to the compressor cylinder 3 intermediate its ends by a pivot 21. The lever 20 includes a handle 22 extending outwardly from the pivot 21 and an inner curved leg 23 projecting inwardly through an opening 24 in the side wall of the compressor cylinder 3. The curved leg 23 curves up under the compressor piston 14 and is adapted to engage and force the compressor piston 14 toward the closed end of the compressor cylinder 3 when the handle 22 is pulled outward from the compressor cylinder 3.

FIG. 1 illustrates the starting lever 20 in its storage position wherein it cannot interfere with the reciprocation of the compressor piston 14. When the lever handle 22 is pulled outward from the compressor cylinder 3, the lever 20 pivots about the pivot 21 and the curved leg 23 forces the compressor piston 14 outward toward the closed end of the compressor cylinder 3. As a result, the engine piston 8 is pulled toward the partition 10' compressing and loading the spring 12.

Latch means is provided to lock the piston rod 9 in a starting position wherein the spring 12 is compressed and loaded for later pushing the engine piston 8 outward toward the engine head 7 along its compression stroke. This latch means includes a latch washer 26 having a bore 27 receiving and surrounding the piston rod 9. The washer 26 is located on the compressor side of the partition 16 and seats against a fulcrum 28 located on the partition near the lever 20. The washer 26 can tilt about the fulcrum 28 between a tilted position, wherein the walls of the bore 27 are cocked against the rod 9 with sufficient force to grip and latch the piston rod 9, and a position at right angles to the rod 9, wherein the rod is released by the walls of the bore 27. When the washer 26 is in its tilted position shown in FIG. 5, the compression of the spring 12 forcing the piston 9 toward the engine cylinder 2 acts to further tilt or cock the washer 26 so that it is self-locking.

A spring 29 is mounted on the partition 10 on the opposite side of the piston rod 9 from the fulcrum 28 and acts on the washer 26 urging it toward its tilted and latched position. The washer 26 is forced to its unlocked position, shown in FIG. 1, by engagement with the leg 23 of the starting lever 20 when the lever 20 is located in its storage position.

The curvature of the leg 23 and the pivot 21 are arranged or located eccentrically relative to each other so that the leg 23 lifts off the washer 26 during its initial movement away from its storage position. Hence, the latch washer 26 is tilted to its latching position as soon as an operator begins to turn the starting lever 20. When the piston rod 9 is moved to the full starting position, shown in FIG. 5, the latch washer 26 prevents the piston rod 9 from returning toward the engine head 7 while the starting lever is returned to its storage position, thus preventing the engine from starting until the lever 20 is in its storage position. This prevents the compressor piston 14 from striking the lever 20 during the starting of the engine and kicking the lever 20 to its storage position which might either injure the apparatus or anybody struck by the handle 22.

As the lever nears its storage position, as shown in FIG. 6, the curved leg 23 engages the washer 26 and forces it back to a position at right angles to the piston rod 9 wherein the walls of the bore 27 release the piston rod 9. Once released, the rod 9 is forced toward the engine head 7 by the previously compressed spring 12.

A unique fuel injection system is provided for the engine. The engine piston 8 cooperates with the partition to form an intake air compression chamber 31. Air flows into the chamber 31 through intake ports 32 formed in the partition and closed by a spring-loaded check valve 33 which allows air to enter the chamber 31 and prevents it from flowing in the reverse direction.

The engine piston 8 and the engine head 7 form an internal combustion chamber 34. Intake air flows from the intake chamber 31 to the internal combustion chamber 34 through internal grooves 35 provided in the interior of the engine cylinder 2 when the engine piston 8 moves inward toward the compressor cylinder 3 far enough to uncover the grooves 35. The extent of the grooves 35 determines the point of entry of the intake air into the combustion chamber 34. The engine cylinder 2 includes several exhaust ports 36 extending radially through the wall of the cylinder 2. The location of the exhaust ports 36 lengthwise of the engine cylinder 2 determines the exhaust point of the engine relative to its operation cycle.

The engine head 7 contains a small ignition chamber 38 which communicates with the combustion chamber 34 by means of an interconnecting bore 39. The chamber 38 contains an ignition means such as an electrically operated glow plug 40. The bore 39 contains a tightly fitted sleeve 41, shown in FIG. 2, which contains a central passage 42 and a series of small exterior longitudinal grooves 43. The grooves 43 are small enough to retain fuel by capillary action.

Fuel is fed to the grooves 43 through a check nozzle 45. The nozzle 45 contains a poppet valve 46 which is biased closed by means of a light spring 47. Fuel is fed to the nozzle 45 by a pipe 48 running from a diaphragm pump 49. The pump 49 contains a diaphragm 50 which is acted on by the pressure in the intake chamber 31 through the port 55. Thus the pump 49 pumps fuel to the nozzle 45 during the movement of the engine piston 8 inward toward the compressor cylinder 3. Fuel is fed to the pump 49 through a pipe 51.

The pump 49 is conventional and contains an inlet check valve 52 and an outlet check valve 53. The fuel side of the diaphragm 50 is spring pressed toward the intake chamber 31 by a spring 54.

During the inward stroke of the engine piston 8, the pump 49 feeds fuel under a relatively low pressure to the nozzle 45. The poppet valve 46 remains closed until the 4 pressure in the combustion chamber 34 is relatively low, which happens after the exhaust ports 36 are uncovered by the engine piston 8. When the pressure in the chamber 34 is low enough, the poppet valve 46 opens and fuel flows into the capillary grooves 43. After the poppet valve 46 closes, the fuel remains in the grooves 43 by capillary attraction. The pressure under which the poppet valve 46 opens will be determined by the strength of the spring 47, the pressure of the fuel in the nozzle 45 and pipe 48, and the pressure in the combustion chamber 34.

As the piston 8 begins its outward or compression stroke, the pressure in the combustion chamber 34 rises rapidly whereby a differential of pressure is created between the combustion chamber 34 and the ignition chamber 38. This differential in pressure forces a part of the fuel in the capillary grooves 43 into the ignition chamber 38.

As fuel enters the ignition chamber 38, it is ignited by the glow plug 40 and begins burning. The burning fuel creates a high pressure in the ignition chamber 38 which is higher than the pressure in the combustion chamber 34. This differential in pressure forces the remainder of the fuel in the capillary grooves 43 into the combustion chamber where it begins to burn. Simultaneously, the burning gas in the ignition chamber 38 flows through the central passage 42 into the combustion chamber. By this time, the piston 8 will have reached and passed top dead center and will be forced inward by the burning gas in the combustion chamber 34, thus performing the power stroke part of its cycle.

The embodiment shown in FIG. 7 contains a modified sleeve 41 extending between the combustion chamber 34 and the ignition chamber 38. This modified sleeve 41' eliminates the central passage 42 shown in the FIG. 2 embodiment and, in its place, contains an additional set of longitudinal grooves 55. The grooves 55 are angularly spaced from the fuel storage grooves 43 and serve the same purpose as the central passage 42 in FIG. 2.

Although a plurality of embodiments of the invention are illustrated and described in detail, it will be understood that the invention is not limited simply to these embodiments, but contemplates other embodiments and variations which utilize the concepts and teachings of this invention.

Having described my invention, I claim:

1. A free piston engine comprising:

(a) a cylinder;

(b) a piston reciprocably mounted in said cylinder for movement between inner and outer positions and having a piston rod extending from said cylinder;

(c) resilient means biasing said piston inward in said cylinder;

((1) latch means operative to lock said piston in its outer position;

(e) cocking means for forcing said piston to its outer position against said biasing means and movable to a storage position wherein it does not interfere with the reciprocation of said piston; and

(f) trigger means operative to unlatch said latch means in response to the approach movement of said cocking means to said storage position wherein said piston is released and said biasing means moves it toward its inner position.

2. The engine of claim 1 wherein said cocking means includes (a) a pivoted lever which can be manually operated to force said piston to its outer position wherein said latch means locks it in that position while said lever is returned to its storage position.

3. The engine of claim 2 wherein said trigger means includes (a) an abutment on said lever adapted to engage said latch means and force it to an unlatched position as said lever nears its storage position.

4. The engine of claim 3 wherein said latch means includes (a) a tiltable washer having a bore embracing said piston rod and arranged to release said piston rod when said bore is substantially axially aligned with said piston rod and to lock said piston rod against movement to the inner position of said piston when said bore is angularly inclined relative to the piston ,rod.

5. The engine of claim 4 including (a) means normally urging said lever to its storage position.

6. The engine of claim 4 including:

(a) means normally urging said tiltable washer toward its piston locking position.

References Cited by the Examiner UNITED STATES PATENTS Christensen 230-56 Charles 123-46 Harrington 123-179 Fowler 230-56 Pugh et al. 123-139 Gill 123-139 Taylor 123-179 Marden et al. 123-46 DONLEY J. STOCKING, Primary Examiner. ROBERT M. WALKER, Examiner. 

1. A FREE PISTON ENGINE COMPRISING: (A) A CYLINDER; (B) A PISTON RECIPROCABLY MOUNTED IN SAID CYLINDER FOR MOVEMENT BETWEEN INNER AND OUTER POSITIONS AND HAVING A PISTON ROD EXTENDING FROM SAID CYLINDER; (C) RESILIENT MEANS BIASING SAID PISTON INWARD IN SAID CYLINDER; (D) LATCH MEANS OPERATIVE TO LOCK SAID PISTON IN ITS OUTER POSITION; (E) COCKING MEANS FOR FORCING SAID PISTON TO ITS OUTER POSITION AGAINST SAID BIASING MEANS AND MOVABLE TO A STORAGE POSITION WHEREIN IT DOES NOT INTERFERE WITH THE RECIPROCATION OF SAID PISTON; AND (F) TRIGGER MEANS OPERATIVE TO UNLATCH SAID LATCH MEANS IN RESPONSE TO THE APPROACH MOVEMENT OF SAID COCKING MEANS TO SAID STORAGE POSITION WHERIEN SAID PISTON IS RELEASED SAID BIASING MEANS MOVES IT TOWARD ITS INNER POSITION. 